/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Collections;
using Spring.Data.Support;
using Spring.Util;

namespace Spring.Dao.Support;

/// <summary>
/// Implementation of PersistenceExceptionTranslator that supports chaining,
/// allowing the addition of PersistenceExceptionTranslator instances in order.
/// Returns <code>non-null</code> on the first (if any) match.
/// </summary>
/// <author>Rod Johnson</author>
/// <author>Juergen Hoeller</author>
/// <author>Mark Pollack (.NET)</author>
public class ChainedPersistenceExceptionTranslator : IPersistenceExceptionTranslator
{
    private readonly ArrayList translatorList = new ArrayList(4);

    /// <summary>
    /// Adds the translator to the translator list.
    /// </summary>
    /// <param name="translator">The translator.</param>
    public void AddTranslator(IPersistenceExceptionTranslator translator)
    {
        AssertUtils.ArgumentNotNull(translator, "PersistenceExceptionTranslator must not be null");
        this.translatorList.Add(translator);
    }

    /// <summary>
    /// Gets all registered IPersistenceExceptionTranslator as an array.
    /// </summary>
    /// <value>The IPersistenceExceptionTranslators.</value>
    public IPersistenceExceptionTranslator[] Translators
    {
        get
        {
            return (IPersistenceExceptionTranslator[]) translatorList.ToArray(typeof(IPersistenceExceptionTranslator));
        }
    }

    /// <summary>
    /// Translate the given exception thrown by a persistence framework to a
    /// corresponding exception from Spring's generic DataAccessException hierarchy,
    /// if possible.
    /// </summary>
    /// <param name="ex">The exception thrown.</param>
    /// <returns>
    /// the corresponding DataAccessException (or <code>null</code> if the
    /// exception could not be translated, as in this case it may result from
    /// user code rather than an actual persistence problem)
    /// </returns>
    /// <remarks>
    /// 	<para>
    /// Do not translate exceptions that are not understand by this translator:
    /// for example, if coming from another persistence framework, or resulting
    /// from user code and unrelated to persistence.
    /// </para>
    /// 	<para>
    /// Of particular importance is the correct translation to <see cref="DataIntegrityViolationException"/>
    /// for example on constraint violation.  Implementations may use Spring ADO.NET Framework's
    /// sophisticated exception translation to provide further information in the event of SQLException as a root cause.
    /// </para>
    /// </remarks>
    /// <seealso cref="DataIntegrityViolationException"/>
    /// <seealso cref="ErrorCodeExceptionTranslator"/>
    public DataAccessException TranslateExceptionIfPossible(Exception ex)
    {
        DataAccessException translatedDex = null;
        foreach (IPersistenceExceptionTranslator pet in translatorList)
        {
            translatedDex = pet.TranslateExceptionIfPossible(ex);
        }

        return translatedDex;
    }
}
